1. Field of the Invention
The present invention relates to a nonvolatile semiconductor memory device and a memory system including the nonvolatile semiconductor memory device.
2. Description of Related Art
There has been known a nonvolatile semiconductor memory device that includes a first memory cell array constituted by a plurality of first strings and a second memory cell array constituted by a plurality of second strings (see Japanese Patent Application Laid-open No. 2002-373497). In this nonvolatile semiconductor memory device, the first memory cell array and the second memory cell array are arranged along a bit line.
In the nonvolatile semiconductor memory device of Japanese Patent Application Laid-open No. 2002-373497, a read path of the first memory cell array and that of the second memory cell array are provided in a separate manner from each other. Specifically, a sense amplifier is arranged on one side of the second memory cell array along a direction of the bit line, and a page buffer is arranged on the other side of the first memory cell array. Data read from the second memory cell array is output through the sense amplifier, and data read from the first memory cell array is output through the page buffer.
According to Japanese Patent Application Laid-open No. 2002-373497, the sense amplifier and the page buffer are arranged in such a manner that they sandwich the first and second memory cell arrays. External terminals of the memory device are arranged at positions far from the sense amplifier and the page buffer. Therefore, this causes both the read path of the first memory cell array and that of the second memory cell array to be increased in length, and as a result, it takes time for transferring the read data to outside.